Checks that a page contains a visible text.
Use context parameter to narrow down the search.

```js
I.see('Welcome'); // text welcome on a page
I.see('Welcome', '.content'); // text inside .content div
I.see('Register', {css: 'form.register'}); // use strict locator
```
@param {string} text expected on page.
@param {?CodeceptJS.LocatorOrString} [context=null] (optional, `null` by default) element located by CSS|Xpath|strict locator in which to search for text.
@returns {void} automatically synchronized promise through #recorder
